The toddler and her little brother had been home with their mom when the attack happened.

The girl’s young mother and her ex-boyfriend were fighting over money, a federal criminal complaint says.

The argument escalated, according to the court filing, and the mother stabbed him in self-defense. He then stabbed her repeatedly late Sunday in her Lansing apartment, the document says.

She managed to get away, go to her mother’s home and call law enforcement. But she left behind her two children, the complaint says.

Her 1-year-old son was soon found unharmed in the apartment, the bureau said.

But the boy’s 2-year-old big sister, Wynter Cole-Smith – in a white T-shirt with rainbows, her hair in braids to her shoulders – was gone.

Lansing Police early Monday issued an AMBER Alert, blitzing cell phones, radios, TVs and road signs to aid their search for Wynter and suspect Rashad Maleek Trice, possibly in a white 2013 Chevy Impala.

Alerts like these, the National Center for Missing & Exploited Children says, “are usually resolved within hours.”

And indeed just before dawn Monday, an officer spotted Trice. After a police chase, he crashed into a police vehicle with a stolen Impala some 90 miles from Lansing in St. Clair Shores, Michigan, and was taken into custody after attempting to take an officer’s gun, the federal complaint says.

But Wynter wasn’t with him.

Lansing police, with the FBI and others, knocked on doors and deployed search dogs. They asked strangers for doorbell surveillance videos, launched helicopters with heat-signature technology and drones, even called in a dive team, Chief Ellery Sosebee said Tuesday at news conference.

But no little girl.

“Wynter is one of our kids,” the chief said as families across America gathered to celebrate the Fourth of July. “And we won’t rest until we find her.”

The FBI announced a $25,000 reward for information to locate Wynter.

The hours dragged on.

“We just want to find her,” Wynter’s dad told the Detroit Free Press on Wednesday. Her 22-year-old mom, whom authorities have not named, was nearby as volunteers swept a suburb north of the city hoping to find their daughter, the newspaper reported.

Still, not a trace.

Then that evening, FBI agents made a discovery.

Offering scant details, FBI Acting Special Agent Devin Kowalski told reporters: “This is not the outcome we were hoping for.”

“We are devastated by the tragic news that Wynter Cole Smith was found deceased today,” Ingham County Prosecutor John Dewane said in a statement. “Our hearts are with Wynter’s family as they begin to process and grieve the unnecessary loss of a beautiful two-year old child.”

The investigation, he said, had transitioned from a missing person case to a homicide inquiry.

Trice, 26, has been charged with felony ᴀssault with intent to murder, first-degree criminal Sєxual ᴀssault, first-degree home invasion and other crimes, state court records show.

On Friday, federal prosecutors charged him with kidnapping a minor and kidnapping resulting in death. If convicted of the latter charge, he would face life in prison or death.

Trice, through his attorney, declined to comment on the state charges, but CNN didn’t receive a response on the federal case. Trice is being held without bond, with a court hearing set for July 13.

According to the federal court document, investigators concluded the toddler was likely choked with a pink cell phone charging cord that was found alongside her body. The charging cord was consistent with the pink cord parts recovered from the car, the complaint says.

“It is so difficult to imagine the final moments of little Wynter’s life,” US Attorney for the Eastern District of Michigan Dawn Ison said in a news release.

An FBI agent says in the criminal complaint that cell phone data, information from license plate readers and surveillance video led them to the girl’s body on Wednesday.

Now, Wynter’s relatives are planning a Friday evening vigil.

“We are heartbroken over the loss of our beautiful daughter, granddaughter, cousins, niece and big sister,” her family said Thursday in a statement.

“Wynter’s brief but bright life was taken from her unnecessarily; and we will grieve her death forever.”